Northern Blue-throated Macaws highly interested in the new Penthouse nestbox design at Barba Azul Nature Reserve

Blue-throated Macaws squabbling over their new real estate.
(Tjalle Boorsma – Asociación Armonía)

For eight years, northern Blue-throated Macaws have never shown an iota of interest in nestboxes at Asociación Armonía’s Barba Azul Nature Reserve. What makes this more perplexing is that the southern Blue-throated Macaws love nestboxes. At the southern Laney Rickman Blue-throated Macaw Reserve, Blue-throats have used 26 nestboxes, fledging 81 chicks in the last 13 years.

Armonía began placing nest boxes at Barba Azul in 2009 without a single macaw ever coming close or showing any kind of interest in these new homes. We copied the same characteristics of successful nestboxes at Laney Rickman Reserve, especially of a preferred height of around 13 feet (4 m) above the ground, but without success. In 2012, hypothesizing that the problem was that the birds did not like nestboxes near large closed forest, we put 50 nestboxes within small isolated palm forest islands along Rio Tiniji. But in the same vain, we never once saw a Blue-throat approach, chew, or leave any kind of sign that they had any interest in the nestboxes.

This is very frustrating because as a conservation effort Armonía has a 27,100 acre (11,000 ha) amazing reserve that is protecting food resources and roosting sites for the Blue-throated Macaws, but none of the them stay to breed on the reserve. All the Blue-throats were flying off in November to breed in what we assumed were palm tree stands in cattle ranches north of Barba Azul.

In 2017, Tjalle Boorsma, Armonía’s Conservation Program Director led a research party about 50 miles (80 km) north of Barba Azul searching for breeding birds. He discovered breeding Blue-throats but with a very different nesting behaviour. The nesting cavities, more like open divots, were placed around 40 feet (12 m) from the ground on top of isolated dead royal palm trees. This was nothing like the preferred nesting holes of the southern Blue-throated Macaws at Laney Rickman Reserve. They were breeding in a cavity about three times higher and much more isolated from other trees.

Actual drone images from the expedition. Watch the nesting cavities as Tjalle saw them the first time in 2017.
(Footage: Tjalle Boorsma)

Knowing that macaws are very smart birds, where a lot of their behaviour is learned, not innate, we thought we needed to rethink our whole nestbox approach and that the solution would be to imitate, if not improve upon, the newly found high cavities.

Thankfully, ARTIS Amsterdam Royal Zoo, IUCN-Netherlands and Mohamed bin Zayed Species Conservation Fund trusted our “out of the nestbox” thinking and supported our project to create high penthouse nestboxes. We had to transport from the Bolivian highlands 10, 40-foot (12 m) long Eucalyptus polls.

Installing the “Penthouse Nestboxes” is a colossal job.
(Tjalle Boorsma – Asociación Armonía)

We were able to raise five penthouse nestboxes in 2018 and we have another five nestboxes that will be raised this year once the ground is dry enough. Tjalle, noticing Blue-throated Macaws have a predictable sunset flight path to their roosting site, decided to place the nestboxes directly in their path.

About mid-June Barba Azul reserve guard Carlos Roca reported that he had seen a pair of Blue-throated Macaws perching and investigating a penthouse nestbox. And two weeks later, Tjalle observed three different Blue-throated Macaw pairs not just perching on our nestboxes but entering the hole and squabbling over the prime real-estate.

#BarbaAzulNatureReserve ranger Carlos reports seeing Blue-throated Macaws visiting and popping into new #nestboxes! We…

Posted by Asociación Civil Armonía on Wednesday, 29 May 2019

Nest cavities are a far more valued resource than your typical nesting bird requires. Naturally, large nest cavities are rare, but in our modern world where most large trees are cut for timber, they are truly a limiting factor in macaw reproduction. Many macaws will identify a breeding cavity many months before they are ready to breed. They will continually observe it and visit it every day to make sure it is safe. This has been seen in many species of macaws and often these good cavities are reused over and over again.  So, the fact that these birds are really noticing these nestboxes, observing them, perching on them, going in and even sort of gently fighting over them, really gives us hope that they may use them to nest. We will keep a watchful eye on these penthouse nestboxes and hope that the birds decide to stay in November to start breeding, completing full lifecycle conservation of the species at the Barba Azul Nature Reserve.

Footage of the 2017 February nesting site expedition.
(Footage: Tjalle Boorsma)

If you would like to support the Barba Azul Nature Reserve program – to protect the Beni Savanna and its wealth of threatened wildlife – please donate.

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